A primary purpose of tracing the provenance of an object or entity is to provide contextual and circumstantial evidence for its original production or discovery and history thereafter. Provenance is created by establishing, as far as practicable, the history of an object or entity. In particular, provenance typically includes the sequences of formal ownership, custody, and places of storage for a given object or entity. The practice of tracking provenance has a particular value in the authentication of objects. Comparative techniques, expert opinions, and the results of scientific tests may also be used to aid in authentication, but establishing provenance is essentially a matter of documentation.